China's new air defense zone, stretching far into East Asia's international skies, is a historic challenge to the United States, which has dominated the region for decades.
For years, Chinese naval officers have told their U.S. counterparts they are uncomfortable with America's presence in the western Pacific—and Beijing is now confronting strategic assumptions that have governed the region since World War Two.
China's recent maritime muscle-flexing in disputes over the Paracel islands and Scarborough Shoal in the South China Sea and over Japanese-administered islands in the East China Sea has stirred concern and extensive backroom diplomacy in Washington.
But it took the events of the last week to spark an immediate and symbolic response from the United States—the unannounced appearance in the zone of two unarmed B-52 bombers from the fortified island of Guam, the closest U.S. territory to the Chinese coast.
China's unilateral creation of the zone—accompanied by warnings that it would take "defensive emergency measures" against aircraft that didn't identify themselves—has raised the stakes in a territorial dispute with Japan over tiny, uninhabited islands in the area.
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Even as some suggest Beijing's move is already backfiring, experts in China say it is a part of a long-term effort, carrying broader historic significance for the United States as the traditional provider of Japanese security.
The regional tensions will loom large when U.S. Vice President Joe Biden travels to Japan, China and South Korea early next week.